With recent advances in digital technology, a radiographic image is converted into a digital image signal, which is displayed on a CRT or the like or printed out on a film upon being subjected to image processing (see, for example, Japanese Patent Application No. 11-076881). In addition, recently, a diagnosis support apparatus which automatically extracts a tumor shadow or the like from a radiographic image has been developed. An image containing the tumor shadow or the like extracted by the diagnosis support apparatus is often displayed on a film or CRT.
However, an extracted tumor shadow is not always displayed at proper contrast on a film or CRT. This may make it difficult to diagnose an extracted tumor shadow or the like. In a chest frontal image, for example, a tumor shadow located in the mediastinum or near the periphery of the lung field cannot be presented at proper contrast. This may cause a problem in a medical examination.
In general, in such a case, when a tumor shadow is displayed on a CRT, the tone curve of the CRT is manually changed to suite for a medical examination of the tumor shadow. Furthermore, even if a tumor shadow has been automatically extracted, it may be overlooked because of the difficulty in making observation on the CRT.
When an image containing a tumor shadow is printed on a film, the density of the printed film cannot be changed. This makes it necessary to change the density again and print an image on a film again. This situation poses many problems in terms of operation efficiency and effective use of resources.